kernel/linux.git/include/vdso/helpers.h, branch v6.19.11

vdso/helpers: Add helpers for seqlocks of single vdso_clock

2025-07-09T09:52:34+00:00

Auxiliary clocks will have their vDSO data in a dedicated 'struct vdso_clock', which needs to be synchronized independently. Add a helper to synchronize a single vDSO clock. [ tglx: Move the SMP memory barriers to the call sites and get rid of the confusing first/last arguments and conditional barriers ] Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250701-vdso-auxclock-v1-4-df7d9f87b9b8@linutronix.de

vdso: Rework struct vdso_time_data and introduce struct vdso_clock

2025-03-08T13:37:41+00:00

To support multiple PTP clocks, the VDSO data structure needs to be reworked. All clock specific data will end up in struct vdso_clock and in struct vdso_time_data there will be an array of VDSO clocks. Now that all preparatory changes are in place: Split the clock related struct members into a separate struct vdso_clock. Make sure all users are aware, that vdso_time_data is no longer initialized as an array and vdso_clock is now the array inside vdso_data. Remove the vdso_clock define, which mapped it to vdso_time_data for the transition. Signed-off-by: Anna-Maria Behnsen Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-19-c1b5c69a166f@linutronix.de

vdso/helpers: Prepare introduction of struct vdso_clock

2025-03-08T13:37:40+00:00

To support multiple PTP clocks, the VDSO data structure needs to be reworked. All clock specific data will end up in struct vdso_clock and in struct vdso_time_data there will be an array of VDSO clocks. For now, vdso_clock is simply a define which maps vdso_clock to vdso_time_data. Prepare all functions which need the pointer to the vdso_clock array to work well after the structures get reworked. Replace the struct vdso_time_data pointer with a struct vdso_clock pointer where applicable. No functional change. Signed-off-by: Anna-Maria Behnsen Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250303-vdso-clock-v1-5-c1b5c69a166f@linutronix.de

vdso: Remove remnants of architecture-specific time storage

2025-02-21T08:54:03+00:00

All users of the time releated parts of the vDSO are now using the generic storage implementation. Remove the therefore unnecessary compatibility accessor functions and symbols. Co-developed-by: Nam Cao Signed-off-by: Nam Cao Signed-off-by: Thomas Weißschuh Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/all/20250204-vdso-store-rng-v3-18-13a4669dfc8c@linutronix.de

random: vDSO: minimize and simplify header includes

2024-09-13T15:28:35+00:00

Depending on the architecture, building a 32-bit vDSO on a 64-bit kernel is problematic when some system headers are included. Minimise the amount of headers by moving needed items, such as __{get,put}_unaligned_t, into dedicated common headers and in general use more specific headers, similar to what was done in commit 8165b57bca21 ("linux/const.h: Extract common header for vDSO") and commit 8c59ab839f52 ("lib/vdso: Enable common headers"). On some architectures this results in missing PAGE_SIZE, as was described by commit 8b3843ae3634 ("vdso/datapage: Quick fix - use asm/page-def.h for ARM64"), so define this if necessary, in the same way as done prior by commit cffaefd15a8f ("vdso: Use CONFIG_PAGE_SHIFT in vdso/datapage.h"). Removing linux/time64.h leads to missing 'struct timespec64' in x86's asm/pvclock.h. Add a forward declaration of that struct in that file. Signed-off-by: Christophe Leroy Signed-off-by: Jason A. Donenfeld

vdso/helpers: Fix grammar in comments

2024-02-20T19:56:00+00:00

Signed-off-by: Anna-Maria Behnsen Signed-off-by: Thomas Gleixner Reviewed-by: Vincenzo Frascino Reviewed-by: Kees Cook Link: https://lore.kernel.org/r/20240219153939.75719-2-anna-maria@linutronix.de

lib/vdso: Add unlikely() hint into vdso_read_begin()

2020-01-14T11:20:47+00:00

Place the branch with no concurrent write before the contended case. Performance numbers for Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz (more clock_gettime() cycles - the better): | before | after ----------------------------------- | 150252214 | 153242367 | 150301112 | 153324800 | 150392773 | 153125401 | 150373957 | 153399355 | 150303157 | 153489417 | 150365237 | 153494270 ----------------------------------- avg | 150331408 | 153345935 diff % | 2 | 0 ----------------------------------- stdev % | 0.3 | 0.1 Co-developed-by: Dmitry Safonov Signed-off-by: Andrei Vagin Signed-off-by: Dmitry Safonov Signed-off-by: Thomas Gleixner Tested-by: Vincenzo Frascino Reviewed-by: Vincenzo Frascino Link: https://lore.kernel.org/r/20191112012724.250792-2-dima@arista.com

lib/vdso: Provide generic VDSO implementation

2019-06-22T19:21:05+00:00

In the last few years the kernel gained quite some architecture specific vdso implementations which contain very similar code. Introduce a generic VDSO implementation of gettimeofday() which will be shareable between architectures once they are converted over. The implementation is based on the current x86 VDSO code. [ tglx: Massaged changelog and made the kernel doc tabular ] Signed-off-by: Vincenzo Frascino Signed-off-by: Thomas Gleixner Tested-by: Shijith Thotton Tested-by: Andre Przywara Cc: linux-arch@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-mips@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: Catalin Marinas Cc: Will Deacon Cc: Arnd Bergmann Cc: Russell King Cc: Ralf Baechle Cc: Paul Burton Cc: Daniel Lezcano Cc: Mark Salyzyn Cc: Peter Collingbourne Cc: Shuah Khan Cc: Dmitry Safonov <0x7f454c46@gmail.com> Cc: Rasmus Villemoes Cc: Huw Davies Link: https://lkml.kernel.org/r/20190621095252.32307-3-vincenzo.frascino@arm.com